Self-Cleaning Filter with Segmented Baskets and Transversal Outlet

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Solution Overview

Problem

Existing self-cleaning filters face challenges in handling large liquid volume flows at fine filtration degrees while maintaining a compact size and minimizing pressure loss, as larger filter basket diameters lead to structural stress and impractical handling due to increased weight and volume.

Innovation Solution

The design incorporates multiple axial filter baskets with individual cleaning elements and a transversal outlet configuration that broadens circumferentially and narrows axially, allowing for efficient dirt accumulation and improved flow profiles, enabling larger volume flows with finer filtration without the need for excessively large filter bodies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the filter basket diameter is increased to handle larger liquid volume flows, then the filtered volume increases, but the filter basket wall stress increases and the filter becomes heavier and more difficult to handle

Engineering Contradiction:
Improvefiltered volumeVSAvoidfilter basket weight
Core Design Contradiction:
ProductivityVSWeight of stationary object

Solution Approach 1:

The filter system is divided into multiple filter baskets (typically 3-5 baskets) arranged in parallel within the filter body. Each basket handles a portion of the total flow, allowing the system to process large volumes without requiring any single basket to be excessively large and heavy. The baskets can be individually removed and replaced, making maintenance easier.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the filter basket diameter is increased to handle larger liquid volume flows, then the filtered volume increases, but the structural stress on the filter basket wall increases

Engineering Contradiction:
Improvefiltered volumeVSAvoidfilter basket wall stress
Core Design Contradiction:
ProductivityVSStress or pressure

Solution Approach 1:

By segmenting the total filtration area into multiple smaller baskets, each basket experiences lower wall stress for the same operating pressure compared to a single large basket. The stress is distributed across multiple structures rather than concentrated in one large wall.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of increasing the diameter (horizontal dimension) of a single basket, the system adds more baskets in parallel, effectively utilizing the radial space around the central axis. This dimensional approach allows high productivity without increasing the stress on individual basket walls.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If the filter basket diameter is increased to handle larger liquid volume flows, then the filtered volume increases, but the filter becomes impractical to handle and difficult to fit snugly in the filter body

Engineering Contradiction:
Improvefiltered volumeVSAvoidfilter basket handling
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

Multiple smaller filter baskets are used instead of one large basket. These smaller baskets are much easier to manually handle, position, and remove for cleaning or replacement. Each basket can be independently manipulated without requiring heavy lifting equipment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The multiple filter baskets are nested concentrically around a central cleaning element and axis within the filter body. This nested arrangement allows efficient use of the filter body volume while keeping each individual basket compact and manageable in size.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Volume of stationary object

If a conical reducer is used in the outlet to improve flow distribution, then the volume and dimension are reduced, but the cleaning action is impaired and upstream end becomes non-productive

Engineering Contradiction:
Improvefilter body volumeVSAvoidcleaning action effectiveness
Core Design Contradiction:
Volume of stationary objectVSReliability

Solution Approach 1:

The outlet is positioned asymmetrically, not at the central axis but offset towards one side of the filter body. This asymmetric positioning allows the outlet to be located at the upstream end of the filter baskets, improving flow distribution to all baskets including those at the upstream end, while maintaining compact dimensions.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

Instead of using a conical reducer that creates a long axial outlet, the design uses a transversal outlet positioned at the upstream end. This changes the outlet orientation from axial to transversal, eliminating the non-productive zone and maintaining effective cleaning action across all filter baskets.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration allows for a significant increase in filtered volume with reduced pressure loss and smaller filter dimensions, enabling effective handling and maintaining fine filtration degrees without structural issues, while also optimizing the use of filter basket length for dirt accumulation.

Implementation Method 1

The Bernoulli Filter is automatically self-cleaning by aid of a cleaning element operable by an actuator to travel along the filter basket's centre axis, whereby a travelling annular gap is formed between a cleaning element and an inside of the filter basket wall, thereby significantly increasing the velocity of the liquid in said gap and its proximity. According to the principle of Bernoulli, the increased velocity results in a locally decreased pressure and thus a reversed liquid flow through the filter apertures in the filter basket wall

Methodology Applied
Scientific EffectBernoulli principle: Bernoulli Effect

Data Source

PatentEP2815797B1Self-cleaning filter and method
Publication Date: 2016.05.25 BERNOULLI SYST
  • EP2815797B1 patent drawingFigure 1
  • EP2815797B1 patent drawingFigure 2~3

AI summary

The invention relates to a self-cleaning filter (10) having a filter body (11) with a diameter D, that comprises an inlet (12), an axial filter basket (20a), a transversal outlet (14), a reject outlet (16), and a cleaning element (22a) operable by an actuator (24a) to travel along said filter basket's (20a) centre axis. According to the invention, the outlet (14) comprises an upstream end defined by an opening (86) in the filter body, which opening has a minor axis x and a major axis y, a downstream end piece (82) with a circular cylindrical cross-section having a diameter d, and a transition piece (80) that interconnects said opening (86) with said end piece (82); where D > 1.5d, x < d, and y > 1.1 d. The invention also relates to a method of cleaning the self-cleaning filter.